just buy a cheap bike, learn, upgrade the season after.
stick with a 600. anything less and you’ll get bored real fast and just want to upgrade right away. anything bigger and you may not be able to handle it.
anything will listed will be a great starter bike. but it all depends on how much you have to spend.
The good thing about bikes (especially when you are just buying it for a season) is that it will barely decrease in value so when you sell it the next year you’ll get close to what you paid for it or sometimes more if you play your cards right. And insurance/gas is alot better with a bike than a car.